1. Field of the Invention
This invention relates to an identification light bar as required by 49 C.F.R. xc2xa7571.108 for vehicles over 80 inches in width, and in particular to such an identification light bar having three lenses illuminated by a single light source, such as a single light emitting diode.
2. Description of the Related Art
Section 571.108 of the Code of Federal Regulations requires that all multipurpose passenger vehicles, trucks, trailers and buses having an overall width of over 80 inches be equipped with a set of three red identification lamps which are mounted on the rear of the vehicle in order to alert other motorists to the presence of a wide vehicle. The lamps are to be mounted as close as practicable to the top of the vehicle, at the same height, and as close as practicable to the centerline of the vehicle. The centers of the lamps must be not less than six or more than 12 inches apart. Multipurpose passenger vehicles, trucks and buses having an overall width of over 80 inches must also be equipped with a similar set of amber identification lamps on the front of the vehicle.
Traditionally, these sets of identification lights have been illuminated by incandescent bulbs, with one or more of the bulbs being mounted in each of the three lamps. Incandescent bulbs, however, are prone to failure, and the bulbs must be inspected and replaced regularly. In recent years, lighting manufacturers have begun to substitute light emitting diodes (LEDs) for the incandescent bulbs used in vehicle lighting. LEDs have a rated life of 100,000 hours, which is far superior to that of an incandescent bulb.
LEDs can be used in an identification light system by placing one or more of the LEDs in each of three lamps. The assignee of the present invention produces an identification light bar using LEDs in this manner, the Peterson Manufacturing Co. Piranha(copyright) LED Model 160-3R. Vehicle lamps incorporating multiple LED light sources can be relatively expensive, however and require multiple electrical connections.
There would be distinct advantages to an identification lamp system wherein a single LED was used to illuminate all three of the identification lamps. Such a system would be less expensive to produce, and would draw less current than a multiple LED system. Lower current draw would allow the use of lighter gauge wiring, further lowering the cost of using such a system. Furthermore, use of a single light source reduces the number of electrical connections required to power the identification light system. Fewer connections means both simpler installation and fewer potential failure points.
It has previously been known to pipe light from a single source for use as vehicle marker lighting. U.S. Pat. No. 4,947,293 to Johnson, et al. discloses a vehicle clearance light system wherein light from a single source is piped through a light conducting strip clad in a translucent material having a different index of refraction from the core material. The result is a continuous strip of lighted material around the top of a vehicle which can serve as clearance lighting. Note that as shown in FIG. 2, this device is intended as a supplement to the existing lighting required by vehicle regulations and not as replacement therefor. The continuous strip of light produced by this system is incapable of serving the mandated identification function, since the regulation requires three distinct lamps spaced a specified distance apart.
U.S. Pat. No. 5,122,933 to Johnson discloses a combination clearance light and message system for trucks. In this system, a pair of fiber-optic cables pipe light from a single high intensity source around the perimeter of a truck trailer. The cables are encased within an enclosure having a translucent face plate. The face plate can be provided with a graphic message such as an advertising slogan which is illuminated by light from the fiber optic cables. It is also specified that a portion of the enclosure may be colored to provide the legally required clearance lighting function. It should be noted that this system utilizes a high intensity light source, such as a quartz halogen lamp, to provide illumination to the entire length of a semi trailer. A high intensity system of this kind is not suitable to the more limited task of serving the federally mandated identification light function for wide vehicles.
In a related product, the Assignee of the present invention has for more than one year manufactured a round, two inch diameter, combination clearance and side marker light, the Peterson Manufacturing Co. Piranha(copyright) LED Model 165. This light is designed to function as both a clearance light and a side marker light when mounted on a forty five degree angle. The lamp includes a center LED which is focused onto a portion of the lens having surfaces inclined at a 45 degree angle which act as a prism to deflect portions of the light from the center LED in respective lateral directions, allowing the lamp to be clearly seen from the sides.
The present invention comprises a light bar for a vehicle having three lenses illuminated by a single light source, such as an LED. The lenses may be spaced apart and colored so as to comply with 49 C.F.R. xc2xa7571.108 as identification lamps for vehicles over 80 inches in width. The light bar includes an elongated, transparent body having a center optic, a left distal optic, a right distal optic, a left light pipe extending outwardly from the center optic to the left distal optic, and a right light pipe extending outwardly from the center optic to the right distal optic. Each of the optics is covered by a respective lens.
The light source is aligned with the center optic such that the center optic receives light emitted by the light source and divides the light-into three portions of generally equal intensity. A first portion of the light is emitted from the light bar through the lens covering the center optic, a second portion is transmitted along the left light pipe and emitted from the light bar through the lens covering the left distal optic, and a third portion is transmitted along the right light pipe and emitted from the light bar through the lens covering the right distal optic.
Each of the lenses includes a tubular sidewall and an end wall closing one end of the tubular sidewall. The light bar is mounted on the interior of a front or rear wall of the vehicle with the tubular sidewalls of the lenses extending through respective holes in the vehicle wall. The holes in the vehicle wall are sealed by respective elastomeric gaskets such that only the end walls of the lenses are visible from the exterior of the vehicle. When mounted in this manner, light emitting from the lenses will be seen from outside the vehicle and any light leaking from other parts of the light bar will not.
The tubular sidewall of each lens may include an annular ridge which extends outwardly therefrom, and each grommet may include an internal annular groove sized and shaped to receive the annular ridge of the respective lens. If the annular ridges are formed with a tapered front edge and a square rear edge, the tapered front edges will allow the lenses to be easily inserted into the respective grommets whereas the square rear edges will inhibit the lenses from being pulled out of the grommets, thereby securing the light bar to the vehicle.